Technical requirements for cross section of low-voltage wire harness for automobiles
Automobile wire harness is one of the products with rapid development, largest market demand and convenient installation in the electronic and information age industry. The car is equipped with complete functions, but the electrical circuit hidden in the car body is complex, the size is too large, and it is not easy to replace. The reliability of wire harness is the key component that affects the performance of the whole vehicle, and the quality control of wire harness is very necessary. The requirements of the national standard for the cross section analysis technology of low-voltage automobile wire harness and the cross section analysis technology of crimping connection terminals are as follows:
The size of wire harness shall meet the following requirements: F type crimping terminal section analyzer: the length of main line and protective sleeve shall not be less than 100mm, and shall be 10 times of riveting section computer analyzer. E.g. 100mm, 110mm, 120mm; The length of branch line of terminal slice analysis system should not be less than 30mm; The distance between the contact and the branch point should not be less than 20mm for the metallographic analyzer of the cross section of the automobile low-voltage wire harness between the contacts; When insulating sleeve is required to be installed at the connection of wire and terminal, the length of insulating sleeve shall not be less than 20mm.
The crimping method shall be preferred for the connection between terminals and wires. The analysis technology of crimping terminal section of automobile harness shall be used. The connection shall meet the following requirements: the terminals shall be pressed on the conductor and insulating layer respectively. The automobile harness terminal section analysis system shall not break the conductor, and the insulating layer shall not press the crimping part of the conductor. The wire conductor automobile harness section metallographic analyzer shall be visible, but shall not interfere with the insertion. Cross section analysis of crimping terminal of automobile harness after crimping test of insulation layer for at least 3 cycles. The cross-section of crimping terminal and wire shall meet the requirements of the specification.
The wire harness section metallographic analyzer shall be carried out according to the following methods for the crimping of terminals and conductors and the cross section inspection of crimping points: the production of the sample Wire harness terminal detection equipment: after the tested sample (which should avoid the reinforcing rib of the terminal) is cut off, one side of the sample shall be taken as the sample, and its cross section shall be ground flat, and the automobile wire harness section metallographic analyzer shall be subject to chemical corrosion treatment until sample inspection can be conducted.
According to relevant national technical specifications, wires of different circuits, wires of different voltages, AC wires and DC wires cannot be threaded in the same protective tube. Because different lines have different uses and specifications, their electrical loads are also different. If they are connected together, the lines with large electrical loads will interfere with and damage the lines with small electrical charges. If the power line is blown, it will cause short circuit, spark and fire. The weak current signal line can not go together with the strong current, because the electromagnetic field generated by the strong current will affect the weak current signal and affect the communication and video effects. The sectional area of lighting line and socket line is different, and the load power is not uniform. The socket line is frequently used, which will cause electric shock, short circuit and other phenomena. Therefore, wires with different purposes and functions must not be threaded in the same protective tube.